Dozens of photographers and videographers captured the moment that Marco Rubio strolled onto the convention stage. This was just a walk-through, but the media attention was intense anyway. Rubio, behind the podium, simply listened attentively to a couple of men explaining the set-up.

Marco Rubio has been a senator for two years now, and a national media sensation for even longer. But his introduction of Mitt Romney tonight will be the most prominent speech he has ever delivered. Asked by a reporter what would distinguish this speech from his prior ones, Rubio laughed. “I don’t know,” he responded. “39 million people, probably,” he said, referring to the huge audience anticipated.

Still, Rubio remains adamant that, even if the speech serves as his formal introduction to the national stage, Romney is the focus. “They’re not tuning in to see me,” Rubio tells National Review Online. “They’re tuning in to see Governor Romney. The only thing I’m hoping to do is to introduce him in a way that sets him up to spike the ball.”

For Rubio, the convention speech is part of a larger mission: getting the conservative message out to a wide audience. He is working to achieve that by speaking to media outlets whose viewers span the ideological spectrum. This week alone, Rubio has appeared on BET, NBC, ABC, CBS, CNN, Fox News, The Daily Show, MSNBC, Univision, Telemundo, PBS, and CNBC. He has talked about immigration and the GOP with the New York Times, and about Medicare with MSNBC host Andrea Mitchell. In a media session, Rubio took multiple questions from Spanish-language reporters, answering them in unhesitating Spanish.

“Any opportunity I have to talk about how free enterprise and limited government is the right choice for America and how the Republican party is the logical place for that movement to reside is a chance, I’ll try to take,” Rubio says. “I’ll try to communicate that to as many people as I can and, obviously, the media is an important way to communicate.”

For Rubio, star power is real. As he did a whirlwind series of interviews around the convention floor on Wednesday, the senator couldn’t walk more than a few feet without being grabbed by another reporter. When he held a media availability after his stage walk-through, dozens of reporters crowded around him, forming the kind of packed media scrum that is more typical for presidential candidates than for senators. “How do I pick?” Rubio asked, smiling, as several reporters simultaneously shouted questions at him.

In interviews, Rubio blends good humor with an earnest seriousness. Sometimes he appears to relax during an interview; other times, he seems overly earnest, unable completely to forget the amount of pressure on him. (When Rubio runs into prominent social conservative Ralph Reed just outside the convention, Reed jokes, “We’re counting on you to save Western civilization.”) But if he is bored by hearing the same questions and giving the same answers, Rubio conceals it well, remaining energetic.

Before interviews, he is often playful. In the CNBC studio, he comments that the microphone, a headset with a bud that rests right by his mouth, makes him feel as if he works at Burger King. (A Miami-based company, he adds.) This begins an extended conversation about fast food between Rubio and a couple of CNBC employees. At one point, he starts reciting the old McDonald’s jingle: “Two all beef patties, special sauce, lettuce, cheese . . . ”

At the convention, life around Rubio is circus-like. In between scrambling to get around to his scheduled interviews — which are scattered around the arena — Rubio, walking down hallways and up and down stairs, gives quick interviews in English and Spanish. He greets Tagg Romney when the two run into each other in a back stairway, and when he is given a rare moment without a reporter shoving a recorder in his face, he quickly checks his phone.

Racing up stairs to do an interview, Rubio stops to take a photo with Kansas delegate Ben Sauceda. Sauceda, who is Hispanic, sees Rubio as “a great role model as a conservative leader for our side.” “I’m stoked to hear him,” Sauceda says. “This is who I came to hear, other than, of course, the nomination speeches.” Later, on the way to another TV interview, an aide tells Rubio that a woman in the elevator wants a photo with him. “Yeah, absolutely,” Rubio responds good-naturedly. “In an elevator?” The photo is eventually snapped outside.

As we walk away from the convention center, I ask him how he handles the craziness. “Well, this isn’t every day,” he responds, noting that conventions occur only every four years and that this one is being held in in his home state. “If I had to do this every day, I’d quit,” he says lightly.

Looking forward, he is eager to spend time after the convention talking about the differences between Barack Obama and Romney.

“It’s a bottom-line choice between two very different views of what government should be involved doing in our economy,” Rubio says. “Barack Obama would admit that. He believes that more government spending and more government programs is what it will take to grow our economy. Mitt Romney believes that what grows our economy is when people take their own money and invest it, starting a new business, and if it works they hire people, and those people spend money into the economy, creating prosperity for others.” The Romney argument is “backed up by our history”; Obama’s “ideas have never worked anywhere in the world.”

“And,” Rubio adds, “I just can’t wait to get out there and make that argument.”

— Katrina Trinko is an NRO reporter.